1. Field of the Invention
The present invention relates to a repairing device for a liquid crystal display, and more particularly, to a device for repairing the defects on a thin film transistor substrate of a liquid crystal display.
2. Description of the Related Art
With the advantages of low-power consuming, low-heat dissipation and light weight, liquid crystal displays (LCD) have been widely used in the electronic products and even have replaced the traditional CRT displays.
A liquid crystal display device typically includes a pair of substrates which are maintained in a spaced apart, and parallel relationship with one another. The space between the substrates is commonly referred to as the cell gap. Interposed between the substrates, within the cell gap, is a liquid crystal material which changes its optical characteristics in response to applied voltage signals. Taking a thin film transistor (TFT) liquid crystal display (LCD) as an example, pixel electrodes are disposed on a substrate and color filters are disposed on the other substrate for applying the predetermined signals to the liquid crystal material and for generating images on the TFT LCD. The substrates are made of high quality transparent material, such as glass, acrylic resin (PMMA) and the like.
Referring to FIG. 1, it depicts a manufacturing process of a thin film transistor liquid crystal display 10 in the prior art. The thin film transistor liquid crystal display 10 comprises a thin film transistor substrate 12 and a color filter substrate 14. The thin film transistor substrate 12 has scan lines 22 and data lines 24 perpendicular to the scan lines 22, both of which are electrically connected to the thin film transistor 23 for controlling pixel electrodes 26 for generating images. The color filter substrate 14 comprises a black matrix 42 for defining a plurality of pixel areas which are coated with red filters 44, green filters 46, and blue filters 45, respectively. Then, the thin film transistor substrate 12 and the color filter substrate 14 are aligned and combined with each other.
The image of the liquid crystal display is controlled by millions of pixel electrodes. However, if one of the millions of pixel electrodes or transistors has a defect, the defective dot or pixel will be formed on the liquid crystal display. In fact, according to the type of the defects of the pixel electrodes or transistors, the defective dots or pixels will be formed as bright dots or dark dots. Due to the visual performance, the bright dot is not acceptable for the user. Therefore, in the manufacturing process, the bright dots will be modified into the dark dots by the laser repairing device which is used for changing the electronic property of the thin film transistor or the orientation of the liquid crystal molecules. However, not all the bright dots can be modified by the laser repairing device or process, and the unmodifiable bright dots result in reducing of the quality of the liquid crystal display.
Accordingly, there exists a need for a device and method for repairing the thin film transistor substrate of the liquid crystal display and further increasing the yield of the liquid crystal display.